ISSN:0253-3839    

DOI:10.1080/02533839.1988.9677110

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

An efficient method for finding initial shape of cable system by nonlinear displacement analysis is presented in this study. The supports of a cable system are first moved from a reference position to the specified boundary and the equilibrium position is then determined by the Newton‐Raphson iteration method. During analysis the large displacement effect is taken into account. The determined shape provides the geometry as well as the prestress distribution of the cable system. In general, the prestress of cable members may be too large or too small in the equilibrium position. So some modifications must be carried out in order to obtain a reasonable initial shape with suitable element length and prestress distribution. This method works well and can be applied to any cable system having an arbitrary form.

ISSN:0253-3839    

DOI:10.1080/02533839.1988.9677111

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Finite‐difference techniques based on boundary‐fitted coordinates are used to study the interaction of waves with large fixed two‐dimensional structures submerged in water of finite depth. The physical flow field is transformed to the curvilinear coordinate system in which the computational region is rectangular with a fixed square grid regardless of the movement of the free surface. The free surface of the flow is obtained such that the transformation is computed simultaneously with the flow field for each time step. Wave forces and pressure are calculated from the velocity potential of the flow. The comparison of the results for the wave forces of two cases for submerged structures in water of finite depth with solutions obtained by other methods indicates that these finite‐difference techniques can yield accurate results. To demonstrate the usefulness of the numerical approach, the problems of two submerged horizon‐mounted cylinders in different spacings, which do not have classical solutions, are also analyzed.

ISSN:0253-3839    

DOI:10.1080/02533839.1988.9677112

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The interpretations of dilatometer test (DMT) field data for soil engineering properties are discussed in this paper. A PC version graphic FORTRAN program (DMTG) developed by the author at National Taiwan University is used for the DMT data reduction. A proposal to evaluate the behavior of laterally loaded piles using DMT data is presented. The concept of size effect and correction factors is included in the said proposal. An example of the evaluation of behavior of a laterally loaded pile using DMT data is clearly described. An assessment of the liquefaction potential of sands using both DMT lateral stress index (Kd) and cone penetration test (CPT) corrected cone bearing (Q‘c) is also presented in this paper. A parallel comparison of the liquefaction potential profile from both DMT and CPT data for sand layers is given in this paper.

ISSN:0253-3839    

DOI:10.1080/02533839.1988.9677113

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

In model reference adaptive control systems, because the plant is assumed to be unknown, it is a difficult task to choose a suitable reference model such that the perfect model matching condition (i.e., the plant zeros in |z|≥1 must be the zeros of the reference model) is assured in every adaptive step. In the present paper, an adaptive controller, achieved by minimizing theH2‐norm of the error transfer function between the closed‐loop system and the reference model using the technique of calculus of variations, is developed. It guarantees the stability of a closed‐loop system regardless of whether or not the controlled plant is unstable or nonminimum phase.

ISSN:0253-3839    

DOI:10.1080/02533839.1988.9677114

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

This study investigates the effects of latent heat transfer associated with liquid film vaporization on the heat transfer in the laminar mixed convection flows under the simultaneous presence of the combined buoyancy forces of thermal and mass diffusion. Major nondimensional groups identified areGrT, GrM, Re, ϕ, PrandSc. The results specifically present an air‐water system under various conditions. The effects of wetted wall temperature, Reynolds number and relative humidity of the air at the ambient on the momentum, heat and mass transfer are examined in great detail. Results show that the effects of evaporation of the wetted wall on the laminar mixed convection heat transfer are rather substantial.

ISSN:0253-3839    

DOI:10.1080/02533839.1988.9677115

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

This paper studies the geometric design of a robot with five degrees of freedom. According to kinematic synthesis procedure, an industrial robot with five degrees of freedom was used as an example to illustrate the design concept. From the number synthesis point of view, the robot is one freedom less than adequate to perform a general three dimensional motion. The lack of full degree of freedom will restrict the available twist screws for the end‐effector. The unavailable twists of the robot were discovered based on the reciprocal screw system. Singular configurations of the robot were also examined. The dimensional synthesis of a robot is to decide the joint parameters to obtain a good workspace shape and volume. So far, there are no better rules which govern the relations between the joint parameters and the generation of workspace. Under this circumstance, the workspace geometric properties of a robot provide quantitative evaluation of the success of the dimensional synthesis. In this paper, workspace volume and other workspace properties such as the normalized volume index (NV1), volume centroid, and the higher volume moment of inertia are computed. The volume centroid gives the symmetric nature of the workspace, whereas the higher moment reveals the distribution and the compactness of the workspace valume.

ISSN:0253-3839    

DOI:10.1080/02533839.1988.9677116

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A theoretical framework and an efficient algorithm are presented to solve the problem of sequencing jobs on a single processor. The objective achieved is minimum total tardiness. Jobs must be independent, with deterministic processing times. A brief review of the literature concerning sequencing to achieve minimum total tardiness is presented. This review shows that Emmons’ algorithm generally results in a partial schedule, and an enumerative method, branch and bound method or dynamic programming method, was then applied to help obtain a complete sequence. Thus Emmons’ algorithm is applied as a precursor to several enumerative algorithms. Furthermore, to certain problems (i.e., LPSD: jobs which have the property of a longer processing time but a shorter due date), Emmons’ theorems would not apply before branching the problems. The algorithm presented in this paper effectively applies the partitioning method to eliminate the need for enumerative methods. A set of necessary conditions for an optimal sequence is presented with proofs in the theory section. This is followed by a statement of the algorithm. The algorithm is illustrated with an example problem taken from Ref. [7]. Computational results are then presented which show the efficiency of the algorithm relative to dynamic programming.

ISSN:0253-3839    

DOI:10.1080/02533839.1988.9677117

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

In this paper we shall show how we can find a linear system equivalent to a running key generator consisting of a maximum length (ML), a linear feedback shift register (LFSR), and a nonlinear feedforward state filter function. At the same time, a new analysis, which uses a Walsh orthogonal expansion of the state filter function and its relation to the crosscorrelation function (CCF) between the ML‐sequence and the produced running key sequence, is introduced.

ISSN:0253-3839    

DOI:10.1080/02533839.1988.9677118

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Diakoptics methods for large scale networks have been widely studied and applied over the last decade. Most of the applications used single level diakoptics of a network into subnetworks. The previous works treat networks either by node tearing or by connecting all the tie lines at the same time [1, 6, 9, 12, 14]. In this paper, tearing is applied to hierarchically described networks and a new algorithm based on Gaussian elimination is presented. Using a multilevel algorithm, the new method tears a network into multilevels and always joins two subnetworks by a set of the lines recursively. Finally, the macromodel (solution model) of a large scale network is presented.

ISSN:0253-3839    

DOI:10.1080/02533839.1988.9677119

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor